The invention relates to a pulse generator wheel, preferably for shafts, comprising a circumferential cylindrical wall that is provided with windows that are distributed about the circumference of the cylindrical wall and that are closed axially by a ring.
Pulse generator wheels are used in combination with sensors for measuring the rotary speed and angle position, for example, in motors. The pulse generator wheels have a substantially cylindrical wall with recesses.
As a result of the fixed connection to the shaft, the recesses move past a sensor when the shaft is being rotated and this causes a change of the magnetic flux of the magnets provided in the sensor. These changes are detected by a measuring cell in the sensor and converted into corresponding electrical pulses.
Pulse generator wheels are known whose cylindrical wall is profiled in a wave shape. This wave-shaped profile provides a robust configuration of the pulse generator wheel. Disadvantageous is however the resulting imprecision of the measured result. Depending on the maximum allowable outer diameter there are conflicts with the fit bore that is provided at the bottom side.
Other pulse generator wheels are known in which the wall is formed by fingers that are positioned adjacent to one another at a spacing. Between the fingers the windows are formed that are open in the axial direction. This finger profile has a higher precision in comparison to the wave-shaped profile. Because of the individual fingers, the pulse generator wheel is however very sensitive with regard to mechanical damages or deformations after its manufacture. The fingers are relatively narrow and can therefore easily become bent so that the measuring precision is impaired.
Also, pulse generator wheels are known in which the cylindrical wall has windows that are rectangular recesses within the wall. In contrast to the finger profile, the windows are closed off in the axial direction by a circumferential ring. This ring provides stabilization of the pulse generator wheel. This webs extending between the windows are thus essentially protected with regard to deformation. However, the manufacture of the window profiles is possible only with great expenditure. Also, the precision required for the pulse generator wheels can be achieved only with difficulty. A further problem resides in that the windows are first stamped from a flat sheet metal part. The edge area that contains the windows must then be erected. This erecting process however causes the diameter of the ring that closes off the windows axially to become smaller so that material displacement occurs. This has the result that the outer ring is of an irregular shape and this impairs the precision of measurements carried out with the pulse generator wheel.